Method of testing an unknown sample with an analytical tool

Abstract

The present invention provides a method of testing an unknown sample with an analytical tool The method may include calibrating an analytical tool to a calibration standard having a known concentration of an element therein and obtained with a focused beam, thereby to achieve a calibrated analytical tool, determining an unknown concentration of the element within the unknown sample with the calibrated analytical tool, and correcting the unknown concentration with the calibration standard.

What is claimed is:  
     
       1. A method of testing an unknown sample with an analytical tool, comprising: 
       calibrating an analytical tool, wherein calibrating includes;  
       obtaining a calibration standard having a known concentration of an element therein;  
       obtaining a portion of the calibration standard with a focused beam, wherein the portion is representative of the known concentration; and  
       calibrating the analytical tool with the portion;  
       determining an unknown concentration of the element within the unknown sample with the calibrated analytical tool; and  
       correcting the unknown concentration with the calibration standard.  
     
     
       2. The method as recited in  claim 1  wherein calibrating further includes obtaining a detection limit of the analytical tool with respect to the known concentration. 
     
     
       3. The method as recited in  claim 1  wherein calibrating includes implanting the calibration standard with a known concentration of the element. 
     
     
       4. The method as recited in  claim 3  wherein implanting includes implanting the known matrix with the element to achieve a concentration of about 1E21 atoms/cm 3  of the element. 
     
     
       5. The method as recited in  claim 3  wherein implanting the element includes implanting the element by ion implantation. 
     
     
       6. The method as recited in  claim 1  wherein calibrating includes determining the known concentration using secondary ion mass spectrometry (SIMS) or rutherford backscattering spectrometry (RBS). 
     
     
       7. The method as recited in  claim 1  wherein calibrating includes obtaining the calibration standard with a focused ion beam process. 
     
     
       8. The method as recited in  claim 1  wherein calibrating includes obtaining the calibration standard with a subatomic particle beam or a laser beam. 
     
     
       9. The method as recited in  claim 1  wherein calibrating an analytical tool includes calibrating an analytical tool selected from the group consisting of: 
       energy dispersive spectrometry (EDS),  
       microcalorimetry,  
       auger electron spectroscopy (AES), and  
       x-ray photoelectron spectroscopy (XPS).  
     
     
       10. The method as recited in  claim 1  wherein calibrating includes obtaining a thin portion of the calibration standard having a thickness of between about 50 nm and about 5000 nm. 
     
     
       11. The method as recited in  claim 10  wherein obtaining a thin portion includes obtaining a thin portion having a length of about 20000 nm and a depth of about 5000 nm. 
     
     
       12. The method as recited in  claim 1  further comprising creating a sample holder and placing the calibration standard in the sample holder, wherein creating the sample holder includes; 
       providing a main body having first and second opposing major surfaces, a recess in the first major surface and a main body aperture narrower than the recess and extending from a base of the recess to the second major surface; and  
       constructing a plug that engages an inner wall of the recess to fix the plug with respect to the main body and fix a grid containing the sample between the base and the plug, the plug having a plug aperture extending therethrough that aligns with the main body aperture to form a path to and through the sample for a beam from a selected one of multiple analytical tools.  
     
     
       13. The method as recited in  claim 1  further including a second analytical tool, wherein the calibration standard is used to determine a detection limit of the second analytical tool. 
     
     
       14. The method as recited in  claim 13  wherein the first analytical tool is a secondary ion mass spectrometer and the second analytical tool is selected from the group consisting of: 
       energy dispersive spectrometry (EDS),  
       microcalorimetry,  
       auger electron spectroscopy (AES), and  
       x-ray photoelectron spectroscopy (XPS).  
     
     
       15. A system for testing an unknown sample with an analytical tool, comprising: 
       a first analytical tool capable of determining a concentration of an element located within a calibration standard;  
       a focused beam apparatus capable of extracting a portion from the calibration standard; and  
       a portion extracted from the calibration standard with the focused beam apparatus, the portion being representative of the concentration;  
       a second analytical tool having a detection limit with respect to the concentration; and  
       an unknown test sample having an unknown concentration of the element therein.  
     
     
       16. The system as recited in  claim 15  wherein the first analytical tool is a secondary ion mass spectrometry (SIMS). 
     
     
       17. The system as recited in  claim 15  wherein the calibration standard has a concentration of the element of about 1E21 atoms /cm 3  of the element. 
     
     
       18. The system as recited in  claim 15  wherein the focused beam apparatus is a focused ion beam apparatus. 
     
     
       19. The system as recited in  claim 15  wherein the second analytical tool is selected from the group consisting of: 
       energy dispersive spectrometry (EDS),  
       microcalorimetry,  
       auger electron spectroscopy (AES), and  
       x-ray photoelectron spectroscopy (XPS).  
     
     
       20. The system as recited in  claim 15  wherein the portion is a thin portion having a thickness of between about 50 nm and about 5000 nm. 
     
     
       21. The system as recited in  claim 20  wherein the thin portion has a length of about 20000 nm and a depth of about 5000 nm. 
     
     
       22. The system as recited in  claim 15  wherein the second analytical tool has a sample holder bay and the system further includes a sample holder configured to hold the calibration standard and to cooperatively engage the sample holder bay. 
     
     
       23. The system as recited in  claim 22  wherein the sample holder comprises: 
       a main body having first and second opposing major surfaces, a recess in the first major surface and a main body aperture narrower than the recess and extending from a base of the recess to the second major surface; and  
       a plug that engages an inner wall of the recess to fix the plug with respect to the main body and fix a grid containing the sample between the base and the plug, the plug having a plug aperture extending therethrough that aligns with the main body aperture to form a path to and through the sample for a beam from a selected one of multiple second analytical tools.